solution is next transferred to a dry "Winchester" bottle and labelled.
The label may be rendered permanent by waxing it.

Standard solutions should not be kept in a place exposed to direct
sunlight. Oxidising and reducing solutions, such as those of
permanganate of potash, ferrous sulphate, iodine, hyposulphite of soda,
&c., gradually weaken in strength; the solutions of other salts are more
stable; while those of potassium bichromate and baric chloride are
almost permanent. Solutions of potassium permanganate may be kept for a
month or so without much change. The solutions of hyposulphite of soda
and of iodine should be examined weekly. Ferrous sulphate solutions, if
acidulated with sulphuric acid, may be depended on for two or three
weeks without fresh standardising. Before filling the burette, the
"Winchester" bottle should be well shaken and a portion of about 50 or
100 c.c. poured into a dry beaker or test-glass. Besides the standard
solutions, which are required for titrating an assay, permanent
solutions of the metal or acid of equivalent strength are very useful.
When the finishing point of a titration has been overstepped (_i.e._,
the assay has been "overdone"), a measured volume, say 5 or 10 c.c., of
a solution containing the same metal may be added. The titration can
then be continued, but more cautiously, and the value in "c.c." for the
quantity added be deducted from the final reading.

~Standardising.~--Suppose the object is to standardise a solution of
permanganate similar to that referred to above. A convenient quantity of
iron (say 0.5 gram) would be weighed out, dissolved in dilute sulphuric
acid, and the solution titrated. Suppose 49.6 c.c. of the permanganate
solution are required, then

49.6 : 0.5 :: 100 : _x_